This mini-lesson covers the CCEA topic Cells: the structure and function of animal, plant and bacterial cells, the jobs of each organelle, how cells become specialised, and how we use a microscope — including how to calculate actual size and magnification.
Work through each screen, answer the questions as you go (some are wordy, some are calculations) and collect ⭐ stars. Press Start when you're ready.
Both animal and plant cells share five basic parts. A plant cell has all five plus three extras:
CCEA asks you to compare and contrast bacterial cells with animal and plant cells. A bacterium has a cell wall, cell membrane, cytoplasm and ribosomes, but no true nucleus. Its genetic material is a single loop of DNA in the cytoplasm, and it may carry small extra rings of DNA called plasmids.
Watch out: bacteria do have a cell wall and ribosomes, but the wall is not cellulose, and they have no mitochondria, chloroplasts or true nucleus. Bacteria are also much smaller than animal or plant cells.
Tap a feature, then tap the cell type it belongs to. (Some are shared by all.)
In a multi-celled organism, cells become specialised — their structure is adapted to a particular job. The process of a cell developing its specialised features is called differentiation.
Structure suits function: a sperm has a tail and many mitochondria to swim to the egg; a root hair has a long extension to increase surface area for absorbing water; a red blood cell has no nucleus and is packed with haemoglobin to carry oxygen.
Cells are too small to see with the eye, so we use a light microscope. CCEA expects you to examine and identify cells under a microscope and to calculate the actual size and magnification using a scale bar.
A cell is really 0.05 mm wide. In a photo it measures 20 mm wide.
magnification = 20 ÷ 0.05 = ×400
Units: 1 mm = 1000 µm and 1 µm = 1000 nm. Always convert both lengths to the same unit before dividing. Magnification is image ÷ real, never real ÷ image.
Photomicrographs often show a scale bar instead of a magnification. The bar tells you how long a real distance is on the image. You can use it to work out an object's true size.
A scale bar labelled 10 µm measures 2 mm long on the page (2 mm = 2000 µm).
So 2000 µm on the page = 10 µm real → magnification = 2000 ÷ 10 = ×200.
If a cell measures 40 mm across, its real width = 40 ÷ 200 mm = 0.2 mm = 200 µm.
Tip: measure the scale bar and the object in the same unit, then use the same magnification triangle. The scale bar gives you the magnification; the magnification then gives you any real size.
Tap an organelle on the left, then its matching function on the right.
Animal cell: nucleus · cytoplasm · cell membrane · mitochondria · ribosomes
Plant cell: the same four organelles + cellulose cell wall · chloroplasts · permanent vacuole
Bacterial cell: cell wall, membrane, cytoplasm, ribosomes, single DNA loop + plasmids — but no true nucleus; smaller
Specialised cells: differentiation → sperm, nerve, muscle, root hair, xylem, phloem
Microscopy: magnification = image ÷ real; use a scale bar to find magnification, then real size
You've covered CCEA Cells. Press Finish to see your score.
You've worked through Cells for CCEA GCSE Biology. 🎉
Your stars: 0 / 0
Next: test yourself in the Evaluate stage Confidence Quiz, then lock it in with Verify.